This is a past continuous tense question asking about the reason behind a child's crying at a specific time in the past. It is commonly used by caregivers, parents, or concerned individuals to understand the cause of distress (e.g., hunger, pain, fear, or discomfort). The word "بچہ" (bacha) means "child" (masculine form; for a girl, it would be "بچی" - bachi), and "رو رہا تھا" (ro raha tha) indicates the ongoing action of crying in the past. The tone is usually empathetic or inquisitive, reflecting a desire to address the child's needs or comfort them.